Advanced Materials Research Vols. 295-297

Abstract: This paper probes into the reasons about surface crack on the SS400 steel through analyzing FTSC. The results show that: the surface crack is mainly produced by the high content inclusion in SS400 steel and the fluctuation of inclusion makes the mould flux have bad performance. The protective slag is not filled fully which worsens the condition of heat transfer and makes the solidified shell uneven, thus it is easy to produce crack in the normal forces. Secondly , the slag entrapment and high content of sulfur is the another reason . There are a lot of calcium-aluminate ,silicates, sulfides which have high melting point and low plasticity in crack inside and around and their content gravely deviates from normal state. The effect of inclusion to crack is three times than the slag entrapment and just as the slag entrapment to high sulfur content

Abstract: Seismic design of long-span single pylon cable-stayed bridge at high intensity seismic region has been a difficult issue for designers. There is few references in this aspect at present. Based on the research achievements and the engineering background of a single pylon cable-stayed bridge at high intensity seismic region of East China, a full bridge model is established to analyze dynamic characteristics and seismic responses of the structure. According to the characteristics of excessive displacements of the pylons and main beams and greater plastic deformations of the pylons and the piers when the bridge is under strong earthquake, the damping effect of viscous dampers on the bridge is discussed. The results show that it is necessary to take measures to absorb seismic shocks. The results of this study can be as a reference for seismic design of similar bridges.

Abstract: This project studied on technique of induction cladding alloy layer in steel tube outer wall and property of alloy layer, briefly introduced the principle of technique, technique assemble and outstanding character, and analyzed the microstructure of prepared cladding layer. Result showed that there existed a clear bright transition band between cladding layer and body, and the metallurgical bonding performed very well. The alloy cladding layer microstructure present as form of eutectic between austenite + carbide (some austenite dendritic crystal can be seen in some zone), this technique is applied for steel tube outer wall strengthening. Compared to the current technique, it could protect environment and had advantage of high combining strengthen, speed and low cost and with no interstice and slag inclusion.

Abstract: An unsymmetrical diarylethene derivative bearing both benzothienyl and thienyl moieties, in which a malononitrile group was substituted at the 5-position of the thienyl ring, was synthesized. This compound undergo a reversible electrocyclic rearrangement, generating strongly colored closed-ring isomer upon irradiation with UV-light which show nonfluorescence, while exposure to light in the visible range triggers the cycloreversion to the colorless open-ring form that exhibits strong fluorescence properties. This properties of molecular photochromism were developed that showed both photo switches and fluorescence switches. The erasable and rewritable photo-images on this photochromic diarylethene were successfully demonstrated. This developments are crucial for fundamental research and eventual technical application for high-density optical data storage.

Abstract: A unsymmetrical diarylethene derivative bearing both indole and phenyl moieties was synthesized. At the same time, its photochromic properties and fluorescence switch were investigated in detail. The results showed that this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light in solution, and its absorption maxima were observed at 625 nm in hexane, upon irradiation with 297 nm UV light. The fluorescence intensity of diarylethene decreased dramatically along with the photochromism from open-ring isomer to closed-ring isomer upon irradiation with 297 nm UV light in PMMA. In hexane solution, the open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence at 439 nm when excited at 385 nm.This new photochromic system also exhibited remarkable optical storage character.

Abstract: A novel unsymmetrical diarylethene derivative bearing both indole and thiophene moieties, in which a cyanol group was substituted at the meta-positions of the terminal phenyl ring, was synthesized. At the same time, its photochromic properties and fluorescence switch were investigated in detail. The results showed that this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in solution and in PMMA film, and its absorption maxima were observed at 592 nm in hexane and at 607 nm in PMMA amorphous film, respectively, upon irradiation with 297 nm UV light. The fluorescence intensity of diarylethene decreased dramatically along with the photochromism from open-ring isomer to closed-ring isomer upon irradiation with 297 nm UV light in PMMA. In hexane solution, the open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence at 426 nm when excited at 350 nm.

Abstract: A new unsymmetrical photochromic diarylethene of bis (1,3,5-trimethyl-4-pyrazole)ethane and bis(2-methyl-3-benzofuran)ethane was synthesized, its photochromic, fluorescent and optical strorage properties were examined, the result indicated that the diarylethene 1a changed the color from colorless to violet upon irradiation with 297 nm UV light, in which new absorption maxima were observed at 539nm and 556nm in hexane and PMMA film, respectively. This new photochromic system exhibited remarkable fluorescence intensity and clear fluorescent switches by photoirradiation in hexane. The results showed that the cyclization/cycloreversion process of the compound was determined to be the zeroth/first order reaction. This new photochromic system also exhibited remarkable optical storage character.

Abstract: A new photochromic diarylethene compound, 1-(2-methyl-5-(2,4-difluorophenyl)-3-thienyl)-2-(2-cyanophenyl)perfluorocyclopentene (1a), was synthesized and its photochromism and photo-induced anisotropy was investigated. The results showed that this compound exhibited reversible photochromism, changing from colorless to purple after irradiation with UV light both in solution and in PMMA amorphous film. In hexane, the open-ring isomer of the diarylethene 1a exhibited relatively strong fluorescence at 459 nm when excited at 316 nm. The fluorescence intensity decreased along with the photochromism upon irradiation with 297 nm light and its closed-ring isomer showed weak fluorescence.

Abstract: A new unsymmetrical isomeric diarylethene bearing an electron-donating methoxyl group at ortho-positions of the terminal phenyl ring was synthesized, namely 1-(2,4-dimethyl-5-thiazolyl) -2-[2-methyl-5-(2-methoxyphenyl)-3-thienyl]perfluorocyclopentene (1o). The compound displayed excellent photochromism both in solution and in PMMA film. The isomeric compound also functioned as a fluorescence switch by photoirradiation in solution. In addition, cyclic voltammetry tests showed that the electron-donating methoxyl group at the terminal benzene ring had a significant effect on the electrochemical properties of the isomeric diarylethene.

Abstract: A new unsymmetrical photochromic diarylethene 1-(2-ethyl-3-benzothienyl)-2-[2-octyl-5-formyl-3-thienyl]perfluorocyclopentene (1a) has been synthesized. Its photochromic properties in solution and PMMA film were investigated. Diarylethene 1a changed the color from colorless to blue upon irradiation with 297 nm UV light, in which absorption maxima were observed at 581 nm in hexane and at 582 nm in PMMA film, The results demonstrated that it can be potentially used as polarization holographic optical recording medium.